<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>

<body>
  <ul onclick="alert(1)">
  	<li>1</li>
    <li>2</li>
    <li>3</li>
  </ul>
</body>

</html>
<script>

	//js通过Document类型表示文档。在浏览器中，document对象是HTMLDocument(继承自Document类型)的一个实例
	console.log(document instanceof HTMLDocument);//true;
	console.log(document instanceof Document);//true;
	
	console.log(document.nodeType);//9
	console.log(document.nodeName);//#document
	console.log(document.nodeValue);//null;
	console.log(document.parentNode);//null;
	console.log(document.ownerDocument);//null;
	console.log(document.childNodes);//2
	
	
	
</script>
	